1. Field of the Invention
The present invention relates to castors for furniture or the like, a castor essentially comprising a casing for supporting and protecting wheels, and a swivel that provides the connection between the casing and the furniture.
2. Description of the Related Art
Many such castors are particularly advantageous for use in moving beds, chairs, tables, carts, etc., more particularly in hospital settings or the like.
The structure of such a castor must therefore be designed in such a manner as to enable a piece of furniture such as hospital beds to be moved in any direction. In particular, the castor comprises at least one wheel (generally two wheels in parallel) and means to enable the wheel to rotate about a horizontal axis relative to the casing in order to allow the furniture to be moved in straight line translation, together with means to enable the casing to pivot about a substantially vertical axis relative to the furniture so that the castor can take up any direction relative to the furniture.
Nevertheless, when the furniture has nearly reached its final position, it is sometimes necessary to block the castor against swiveling movement, while enabling its wheel to continue to rotate about its horizontal axis, e.g. in order to enable the bed to be moved further in translation in a perfectly straight line without it being capable of changing its orientation. Once the bed has reached its final position, it is then necessary to block rotation of the wheel in order to prevent the bed from moving again.
In other circumstances, it may be necessary to block the castor against movement in translation and against swiveling movement.
Castors already exist that seek to satisfy the above-defined conditions, such as those described and shown in German patent No. 197 21 033 and in US-A-2009/276977. Nevertheless, they do not give full satisfaction both functionally and structurally speaking.